Cycling through Death Valley in the middle of summer, when temperatures reach a scorching 120 degrees, may not seem like the smartest thing to do.

But there’s a certain logic to it for John Johnson. In one day, the Santa Rosa hill climber plans to ride from the lowest point in North America to Mt. Whitney, the highest in the contiguous United States. Any other season could mean snow at the 14,505-foot peak.

Choosing sunburn over frostbite, Johnson will pedal about 145 miles from Badwater Basin, 282 feet below sea level, to the Whitney Portal at an elevation of about 8,300 feet. From there, he and friends will ditch their bikes and climb the remaining 10 miles on foot.

“I know it’s stupid to ride in the summer. I get that,” said Johnson, 59, a Santa Rosa attorney. “But you have to wait until the snow melts.”

Johnson knows what he’s talking about when it comes to cycling in high elevations. For the past five years, he has been riding the country’s steepest roads in his quest to ascend the top 100 hill climbs in America.

Johnson has nearly achieved his goal, climbing about 90 of the most grueling mountains in 13 states, including Hawaii’s Mauna Kea, which at 13,780 feet is considered the world’s most difficult climb. Johnson, a 1975 Montgomery High School graduate and former Navy lawyer, has done it three times.

“It’s just a brute,” he said. “Picture a continuous climb from sea level with sand and gravel for five miles.”

Got that visual? If not, Johnson has an answer. His website, Pjammcycling.com, features photos and videos of all the climbs, and is fast-becoming a key source for people in the cycling community who are researching climbs.

It averages about 750 hits a day and has been viewed by hundreds of thousands of enthusiasts since its launch about two years ago. The web address contains the initials of the partners in Johnson’s firm, Perry, Johnson, Anderson, Miller and Moskowitz.

Johnson plans to expand the site to cover climbs around the globe. He has a whirlwind trip to Canada this month and will ride Italy in August. Over the next five years, he plans to ride the Andes, the Himalayas and the mountains of France and Spain, and once he is done, he may write a book on the world’s toughest climbs.

“Nobody’s done that book,” Johnson said. “It would be my end game.”

Johnson said his passion for the uphill ride started as an efficient way to work out. With a busy legal practice, he didn’t have time to go to the gym. So he started riding the hills near the Montecito Heights home where he lives with his wife, Rochelle, and still rides to his downtown Santa Rosa office most days.

Johnson was hooked. He rode all of Sonoma County’s toughest rides and has competed in the grueling Terrible Two Hundred double-century ride, among others.

Eventually, he sought challenges throughout the country, scaling hills from Hawaii to New Hampshire.

For his 60th birthday next year he’ll return to the second hardest climb, Haleaka on the Big Island, to ride from sea level to 10,000 feet and then around the island in a course stretching 170 miles.

“My philosophy is, if I can do it at 60, then I’m not 60,” he said.

Friends consider Johnson many years younger than his age when it comes to cycling. Fellow rider and attorney Peter Kuykendall said Johnson is known for taking on physical tests that seem impossible.

Kuykendall, a 34-year-old competitive cyclist, once challenged Johnson to race him up Pine Flat Road, considered the No. 1 climb in Sonoma County. Johnson completed the 24-mile round trip, which includes a 3,000-foot climb, before Kuykendall was halfway done.

“His stamina is unparalleled,” Kuykendall said. “Anyone who has attempted to keep up with him would agree.”

For now, Johnson is training for the July 25 Death Valley to Mt. Whitney ride, which will play out over a 24-hour period in the heat of summer. Mt. Whitney is ranked No. 13 among the top 100, but Johnson is adding the 10-mile hike at the end for an extra challenge.

In preparation, he rides daily and runs up and down the stairs in his four-story office building, which is decorated with photos of famous athletes who contributed to society.

But for a man who has done the nation’s most difficult climb — Onion Valley in the eastern Sierra — five times, it should be no problem. He’s going with a small group of fellow riders, and his wife has agreed to join him on the hike only.

“I’ll probably burn off a few calories,” he deadpans. “It’s going to be super hot. Frankly, I don’t know if I’ll be able to do it. There’s my age and probably a few other excuses.”

You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com.